| 摘要 |
A method of displacement bleaching digested, washed cellulosic pulp. Pulp is continuously passed through successive bleaching stages, each bleaching stage having a displacementextraction loop. Bleaching chemical is added to the pulp in each bleaching stage to effect bleaching. Minimization of chemical consumption within an oxidative displacement-extraction loop is important in displacement bleaching, and this is accomplished by controlling the reaction rate with temperature. The temperature in a given oxidative displacement-extraction loop (i.e. with Chlorine dioxide bleaching chemical) is maintained in the range of about 120.degree.F to less than 160.degree.F, preferably about 135 140.degree.F. A 0.5% net savings within the given displacement-extraction loop may be effected with pulp of the same quality, and a corollary savings in energy is also effected. |
